Why is My Boiler Making Rumbling Noises?

Is your boiler making a sound like an overgrown tea kettle boiling over? If so, you have a bit of a problem. That sound is called kettling, and it is a symptom of a serious issue afflicting a boiler system. We highly recommend that you call on a professional technician for a repair appointment as soon as you notice this sound coming from your boiler. But while you’re waiting for your technician to arrive and fix the problem, read on to find out why kettling is such a big threat to the health of your boiler system.

Why Kettling Happens

It may come as a surprise, but most boilers are not designed to, well, boil water. Instead, they heat water to just under the boiling point before circulating it throughout the home and the different terminal points (radiators, baseboard heaters). Kettling happens when water becomes trapped in the heat exchanger of the system long enough to boil. Typically, this is the result of hard water causing the formation of limescale in the pipes. The more the mineral deposits on the inside of the pipe build up, the more restricted the flow will become. Water expands around 1400 times in volume when it evaporates into steam, which obviously can generate an immense amount of pressure when it happens in an enclosed environment. As the water boils in the heat exchanger, it puts rising amounts of pressure on the pipe that it was not designed to cope with. That’s what causes that rumbling sound. It’s the pipe struggling to contain all the steam.

What Happens If It Isn’t Treated

Well, as you can imagine, cranking up the pressure in a part of the system that wasn’t designed to handle it is going to have some pretty nasty results. Your boiler isn’t going to explode or anything. Most systems have failsafes in place that will automatically shut down the system in cases like that. However, what will happen if the kettling isn’t dealt with isn’t much better. You’re most likely going to have to replace your heat exchanger if you don’t have the root problem dealt with fast enough, due to the damage that kind of pressure can create. You may also have damage in other parts of the system, depending on how widespread whatever was clogging up the boiler was. Regardless, it’s best that you call for repairs as soon as you can before it gets that bad.

As with any heating issue, responding quickly is the best way to make sure that damage to your boiler is as minimal as possible. Even if you’re not entirely sure whether your boiler is in danger, you should call for professional heating repair services just to be safe.